For an imaging unit using a solid-state imaging element (representatively a camera module), an optical filter that transmits or shuts off a wavelength of a specified range (for example, a light selective transmission type glass) is used. Examples thereof include optical filters for imaging unit, such as a color filter for color image production, an optical filter for sensitivity correction that transmits a visible light and shuts off a near infrared light, etc.
As the optical filter for sensitivity correction, for example, optical filters that selectively shut off near infrared rays, in which CuO, etc. is added to a fluorophosphate-based glass, a phosphate-based glass, or the like, are known (see Patent Document 1).